Undercooling and solidification behavior of magnetostrictive Fe–20 at.% Ga alloys
Undercooling and solidification behavior of magnetostrictive Fe–20 at.% Ga alloys
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DOI：
10.1016/j.jallcom.2004.02.021
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发表时间：
2004-10
影响因子：
6.2
通讯作者：
W. Ma;Hongxing Zheng;M. Xia;Jianguo Li
中科院分区：
文献类型：
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作者：
W. Ma;Hongxing Zheng;M. Xia;Jianguo Li
采用电磁悬浮熔炼结合助熔剂法，Ga合金通过加热-冷却循环进行过冷。样品在冷却至1173 K后，在冰水混合物中淬火以保持快速凝固的微观结构。最大体积过冷度达到337 K。在0- 337 K的过冷度范围内，Fe-20 at.%已被调查。在整个过冷度范围内，凝固组织均为等轴晶。当过冷度小于221 K时，晶粒尺寸随过冷度的增加而平缓减小，且分布均匀。当过冷度为230- 315 K时，细小的等轴晶与异常大晶共存，异常大晶的面积分数随过冷度的增加而增加。当过冷度超过320 K时，只有大晶粒存在。特别是当过冷度在173- 221 K范围内时，晶粒具有择优取向。Fe-20at.%通过对过冷Fe-20 at.% Ga熔体在过冷度为205 K时，[001]择优取向偏离棒轴约11.42°。
Using electromagnetic levitation melting combining fluxing method, the Fe–20at.% Ga alloy was undercooled through heating–cooling cycles. The samples, after recalescence, cooled down to about 1173K, and then quenched into ice–water mixtures to maintain the microstructure of rapid solidification. A maximum bulk undercooling of 337K was achieved. Within the undercooling range of 0–337K, the microstructure evolution of bulk undercooled Fe–20at.% Ga was investigated. Over the whole range of undercooling, the solidification microstructures were equiaxed grains. When the undercooling was less than 221K, the grain size decreased smoothly with increasing undercooling and had homogeneous distribution. When the undercooling reached the range of 230–315K, the fine equiaxed grains and abnormal large grains coexisted, and the area fraction of abnormal large grains increased with increasing undercooling. When the undercooling exceeded 320K, only large grains existed. Especially, when the undercooling was in the range of 173–221K, the grain had preferred orientation. The Fe–20at.% Ga alloy rods with [001] preferred orientation was prepared by exciting the undercooled Fe–20at.% Ga melt at undercooling 205K and the [001] preferred orientation was approximately 11.42° away from the rod axis.